Warren Co., N.J., Horse Tests Positive for EHV-1

The New Jersey Department of Agriculture has quarantined a Warren County farm after a 22-year-old horse was diagnosed with the highly infectious equine herpes myeloencephalopathy (EHM), the often deadly neurologic form of equine herpesvirus-1 (EHV-1). The horse had not left the premises in years.

The Thoroughbred mare was euthanized March 31 after she exhibited a rapid progression of neurologic signs typical of EHM; she was subsequently tested positive for EHV-1. There are a number of other horses present at the facility, none of which have shown signs of the disease.

This is the third case of EHM in New Jersey this year. An EHM-positive horse in Somerset County prompted quarantines at two farms in January, and two other farms were quarantined in February due to a sick horse in Gloucester County. No other horses in the two unrelated cases showed signs of the illness and the quarantines were lifted after 21 days of quarantine.

“The department took swift action to prevent the disease from spreading to other horses by enacting a quarantine, which stops movement of horses in and out of the farm and puts in place preventive measures to contain the virus,” said New Jersey Secretary of Agriculture Douglas H. Fisher

The EHV-1 virus spreads quickly from horse to horse, has a high morbidity, and can cause a wide range of clinical signs, ranging from a complete lack of clinical signs to respiratory problems, especially in young horses, and spontaneous abortions in pregnant mares. The neurologic form of EHV-1 can cause an acute paralytic syndrome, which results in a high mortality. The incubation period of EHV-1 is typically two to 10 days. The virus spreads readily through direct contact with infected materials. While highly infectious, the virus does not persist in the environment and is neutralized by hand soap and alcohol-based hand sanitizers. The virus does not affect humans and other domestic animals, with the exception of llamas and alpacas.

Concerned owners should consult with their veterinarian prior to taking any action as the clinical signs of infection with the neurologic form of EHV-1 are common to many other diseases. EHM is a reportable disease in New Jersey. If an owner has a horse that is exhibiting neurologic signs or suspects EHV-1, they are directed to call their veterinarian immediately.

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